Shareholders' equity - Dividends (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	May 02, 2015		Jan. 31, 2015	May 03, 2014
Equity [Abstract]
Cash dividend per share (usd per share)	$ 0.22	[1]	$ 0.18	$ 0.18	[1]
Total dividends	$ 17.6	[1],[2]	$ 14.4	$ 14.4	[1]
Dividends declared	$ 17.6			$ 14.4

[1] Signet’s dividend policy results in the dividend payment date being a quarter in arrears from the declaration date. As a result, the dividend declared in the fourth quarter of Fiscal 2015 of $0.18 per share was paid on February 26, 2015 in the aggregate of $14.4 million.

[2] As of May 2, 2015 and May 3, 2014, $17.6 million and $14.4 million, respectively, has been recorded in accrued expenses and other current liabilities in the condensed consolidated balance sheets reflecting the cash dividends declared for the first quarter of Fiscal 2016 and Fiscal 2015, respectively.